Despite the availability of PZB, ETCS and their international counterparts, train collisions are an unfortunate reality on the world’s railway lines. TrainCAS, which has been conceived and developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V. – DLR) and its spin-off company “Intelligence on Wheels”, prevents this from occurring and does so at a manageable cost per vehicle and without the need for any trackside investments. Since 2016, it has proven itself in daily use on the Harz Narrow Gauge Railway’s (Harzer Schmalspurbahnen – HSB) 140-kilometre long network...